Electron gun assembly including two part threaded electrode

ABSTRACT

An electron gun assembly for a cathode-ray tube having a removable cathode-grid assembly which has a plurality of stem leads connected with the respective electrodes and led out to the outside at the stem and which is supported by multihold glass bars, and an anode and focusing electrode assembly which has a plurality of side leads connected with the respective electrodes and led to the outside from the side and which is supported by multihold glass bars.

United States Patent [72] Inventors Tsutomu Nishino;

Kokiti Kinoshita; Haruo Maeda, Kadoma,

Osaka, Japan [21] Appl. No. 839,015

[22] Filed July 3, 1969 [45] Patented May 18, 1971 [73] Assignee Matsushita Electric Industrial Compan Limited Kadoma, Osaka, Japan [32] Priority July 10, 1968 [54] ELECTRON GUN ASSEMBLY INCLUDING TWO PART THREADED ELECTRODE 1 Claim, 3 Drawing Figs. v [52] US. Cl 313/83, 313/237, 316/28 [51] Int. Cl ..H0lj 29/46, HOlj 1/00,H0l j 8/50 [50] Field of Search 313/82, 82 (BFCl 8'3 [56] References Cited UNITED STATES PATENTS 2,211,325 8/1940 George 315/14 Primary Examiner-Robert Sega] Attorney-John Lezdey ABSTRACT: An electron gun assembly for a cathode-ray tube I having a removable cathode-grid assembly which has a plurality of stem leads connected with the respective electrodes and led out to the outside at the stem and which is supported by multihold glass bars, and an anode and focusing electrode assembly which has a plurality of side leads connected with the respective electrodes and led to the outside from the side and which is supported by multihold glass bars.

Patented May 18, 1971 3,579,009

MWTQZRNEY ponents in addition to the electron gun. If such an electronic gun has a defect on a cathode of the electron gun after it has been sealed under a vacuum, the whole device is useless and has to be discarded which is expensive. Even if it is desired to replace the electron gun of the electronic device, it is almost impossible because the conventional electron gun has many parts or components of accessories attached to the electrodes.

ln the conventional electron gun used in the cathode-ray tube, the electrodes are connected to the outside by means of stem leads for applying the voltages to the electrodes so that it is difficult to remove the cathode-grid assembly from the overall assembly to replace it by cutting the glass envelope.

This invention eliminates above and other disadvantages of the conventional electronic devices having an electron gun and the object of the present invention is to provide anelectron gun assembly for a cathode-ray tube having a removable cathode-grid, assembly.

One advantage of the present invention is that the electron gun assembly has a removable cathode-grid assembly which has a plurality of stem leads connected with the respective tron gun-from which the removable cathode-grid assembly is separated.

Reference is now made to FIGS. 1 through 3, which show one example of an electron gun assembly for a cathode-ray tube having a removable cathode-grid assembly according to the present invention. The cathode-ray tube has a glass envelope 11 and an electron gun assembly 12, the electron gun assembly 12 comprises a removable cathode-grid assembly 13 which has a plurality of multihold glass bars 14, a cathode 15, a grid electrode 16 supported by the multihold glass bars 14, another grid electrode 17 supported by the multihold glass bars 14 and formed at one end with a thread 18, and a plurality of stem leads 19 connected with the cathode l5 and the respective electrodes 16 and 17 and led to the outside at the stem 20, and an-anode and focusing electrode assembly 21 which has a plurality of multihold glass bars 22, an electrode 23 supported by the multihold glass bars 22 and formed at one end with a thread 24 for engaging with the thread 18, an anode 25 sup orted by the multihold gkllass bars 22, a focusing electrode 6 supported by the multi old glass bars 22 and a pluportion of the cathode-ray tube 10 is cut open, the cathodeelectrodes and led out to the outside at the stem of the tube which is threadened so as to be readily removable and attachable and which is supported by multihold glass bars.

Another advantage of the present invention is that the electron gun assembly has an anode and a focusing electrode assembly which has a plurality of sealed side leads connected with the respective electrodes and led radially to the outside from the side of the tube disposed20-30 mm from the stern toward the screen of the cathode-ray tube and which is supported by multihold glass bars. Thus, when the cathode electrode is defected or worn out and is intended to be replaced, the cathode-grid assembly may be replaced after the assembly is cut out from the tube and then the tube may be readily repaired, evacuated and sealed.

The features and advantages of the present invention will become apparent from the following description used in con junction with the accompanying drawings, in which:

H6. 1 is a side sectional view of one example of a cathoderay tube having an electron gun with a removable cathodegrid assembly constructed in accordance with the present ingrid assembly 13 may be removed from the electron gun assembly 12 by unscrewing the cathode-grid assembly 13 threaded to the anode and focusing electrode assembly 21 at the engagement betweenthe thread 18 of the grid 17 and the thread 24 of the electrode 23. Then, after the cathode-grid assembly 13 is replaced by screwing a new one to the anode and focusing electrode assembly 21 at the thread 24 of the electrode 23, the cathode-ray tube 10 may be repaired, evacuated and sealed.

We claim:

1. An electron gun assembly for a cathode-ray tube having a glass envelope comprising:

a removable cathode-grid assembly which has a plurality of multihold glass bars, a cathode, a gridsupported by the multihold glass bars, an electrode supported by the multihold glass bars and formed at one end with a thread and a plurality of stem leads connected with the cathode and the respective electrodes and led out to the outside of the tube at the stem, and

an anode and focusing electrode assembly which has a plurality of multihold glass bars, an electrode supported by the multihold glass bars and formed at one end with a thread for engaging with the thread of said removable cathode-grid assembly, an anode supported by the multihold glass bars, a focusing electrode supported by the multihold glass bars and a plurality of leads connected with the respective electrodes and sealed and led radially to the outside of the tube from the side of the envelope. 

1. An electron gun assembly for a cathode-ray tube having a glass envelope comprising: a removable cathode-grid assembly which has a plurality of multihold glass bars, a cathode, a grid supported by the multihold glass bars, an electrode supported by the multihold glass bars and formed at one end with a thread and a plurality of stem leads connected with the cathode and the respective electrodes and led out to the outside of the tube at the stem, and an anode and focusing electrode assembly which has a plurality of multihold glass bars, an electrode supported by the multihold glass bars and formed at one end with a thread for engaging with the thread of said removable cathode-grid assembly, an anode supported by the multihold glass bars, a focusing electrode supported by the multihold glass bars and a plurality of leads connected with the respective electrodes and sealed and led radially to the outside of the tube from the side of the envelope. 